Edible dispersions comprising oil and structuring agent are well known. Examples of well-known products that substantially consist of such edible dispersions are water-in-oil emulsions, such as for instance margarines and spreads. These edible dispersions typically have an oil phase that is a blend of liquid oil and fat that is solid at normal ambient temperature (20° C.). This solid fat, often also designated as hardstock, acts as structuring agent, and its function is to stabilise the dispersion. For a margarine or spread, ideally the structuring agent has such properties that it should have melted or dissolved at mouth temperature, otherwise the product has a heavy, waxy mouthfeel.
Other known dispersions comprising oil and structuring agent are disclosed in EP-A-775444 and WO 98/47386. Herein the dispersed phase is a dry particulate matter, such as e.g. flour, starch, salt, spices, herbs etc.
Generally, the edible dispersions comprising structuring agent are prepared according to prior art processes that encompass the following steps:    1) mixing/dispersion of the aqueous phase and/or the solid phase and the oil phase, at a temperature where the oil phase, including the structuring agent is liquid;    2) formation of a fat crystal network to stabilise the resulting dispersion and give the product some degree of firmness;    3) modification of the crystal network to produce the desired firmness and confer plasticity.
In case the dispersion is a low-fat water-in-oil emulsion spread (i.e. with a oil content of 45 wt % or less), normally in step 1) a oil-in-water emulsion (premix) is formed, which in step 2) is inverted, so that a transition of the emulsion from oil-in-water to water-in oil (inversion) occurs. Inversion has a number of disadvantages: it is difficult to control and rework (i.e. material that is not packed, but returned to the premix, needs to be reinverted, which may lead to processing complications.
The steps 1)-3) are usually conducted in a process that involves apparatus that allow heating, cooling and mechanical working of the ingredients, such as the churn process or the votator process. The churn process and the votator process are described in Ullmanns Encyclopedia, Fifth Edition, Volume A 16 pages 156-158. Using these techniques excellent dispersions (spreads) having high emulsion stability and good melting properties in the mouth can be prepared.
However, a disadvantage of the known processes is that the process involves a heating step and a cooling step and therefore requires a lot of energy. In a dispersion with for instance 4 wt. % structuring agent the whole weight of the dispersion (100 wt. %) needs to be heated and cooled.
Another disadvantage of the known processes is that the choice of fats that can practically be used as structuring agent is rather limited. If the melting point of the structuring agent is too high the melting properties in the mouth are unsatisfactory. If on the other hand, the melting point is too low, the emulsion stability will be negatively affected. Moreover the amount of saturated fatty acids in the structuring agent is usually relatively high. Saturated fatty acids are a known risk factor for cardiovascular health.
Further disadvantage of the known processes is that the product may deteriorate due to the changes in temperature caused by the heating and cooling step and that heat-sensitive ingredients cannot be incorporated.
Additionally, when low-fat spreads are prepared an inversion step is usually needed, which is difficult to control and has rework problems.
Co-pending application PCT/EP2004/006544 describes edible dispersions, including water-in-oil emulsions, that comprise a structuring agent having a microporous structure of submicron size particles. The water-in-oil emulsion may be a table spread. In the examples pourable emulsions and pourable dispersions were described. The edible dispersions may for instance be prepared by mixing an oil phase with structuring agent particles with a separately prepared water phase.